title: Determination of endocannabinoids in nematodes and human brain tissue by liquid chromatography electrospray ionization tandem mass spectrometry.
abstract: A simple and highly sensitive liquid chromatography/tandem mass spectrometric (LC/MS/MS) method was developed to compare endogenous cannabinoid levels in nematodes and in brains of rats and humans, with and without prior exposure to ethanol. After liquid-liquid extraction of the lipid fraction from homogenized samples, a reversed-phase sub 2 μm column was used for separating analytes with an isocratic mobile phase. Deuterated internal standards were used in the analysis, and detection was made by triple quadrupole mass spectrometer with multiple reaction monitoring (MRM). Ionization was performed with positive electrospray ionization (ESI). The nematode Caenorhabditis elegans fat-3 mutant, that lacks the necessary enzyme to produce arachidonic acid, the biologic precursor to 2-arachidonoyl glycerol and anandamide, was used as an analyte-free surrogate material for selectivity and calibration studies. The matrix effect was further investigated by in-source multiple reaction monitoring (IS-MRM) and standard addition studies. Selectivity studies demonstrated that the method was free from matrix effects. Good accuracy and precision were obtained for concentrations within the calibration range of 0.4-70 nM and 40-11,000 nM for monitored N-acylethanolamides (NAEs) and acyl glycerols, respectively.
authors.affiliation: School of Pharmacy, Faculty of Health Sciences, University of Eastern Finland, Kuopio, Finland. marko.lehtonen@uef.fi
authors.forename: Marko
authors.initials: M
authors.lastname: Lehtonen
authors.forename: Markus
authors.initials: M
authors.lastname: Storvik
authors.forename: Hanna
authors.initials: H
authors.lastname: Malinen
authors.forename: Petri
authors.initials: P
authors.lastname: Hyytiä
authors.forename: Merja
authors.initials: M
authors.lastname: Lakso
authors.forename: Seppo
authors.initials: S
authors.lastname: Auriola
authors.forename: Garry
authors.initials: G
authors.lastname: Wong
authors.forename: James C
authors.initials: JC
authors.lastname: Callaway
mesh_terms: D000704:Analysis of Variance; D000818:Animals; D001923:Brain Chemistry; D017173:Caenorhabditis elegans / Q000737:chemistry / Q000378:metabolism; D063385:Cannabinoid Receptor Modulators / Q000032:analysis* / Q000378:metabolism; D002853:Chromatography, Liquid / Q000379:methods*; D004355:Drug Stability; D063388:Endocannabinoids; D005260:Female; D006801:Humans; D016018:Least-Squares Analysis; D008297:Male; D051381:Rats; D015203:Reproducibility of Results; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D053719:Tandem Mass Spectrometry / Q000379:methods*
chemical_list: D063385:Cannabinoid Receptor Modulators; D063388:Endocannabinoids